History: 3 year old girl with a history of large head, developmental delay, phase out spells, and falls.

Findings: • Partial agenesis of the Corpus Callosum
• Cerebellar tonsil herniation through foramen magnum to a mid-dens level.
On the intraoperative images, note that the CSF flow velocity is now normal after the bony decompression.

Ddx: There are a variety of classifications of Chiari malformations. See factoid for details.

History: 3 year old girl with a history of large head, developmental delay, phase out spells, and falls.

Findings: • Partial agenesis of the Corpus Callosum
• Cerebellar tonsil herniation through foramen magnum to a mid-dens level.
On the intraoperative images, note that the CSF flow velocity is now normal after the bony decompression.

Ddx: There are a variety of classifications of Chiari malformations. See factoid for details.